Electric fence energizer



July 8, 1952 1 J. scHlLLlNG 2,602,844

ELECTRIC FENCE ENERGIZER original Filed Nov. 26, 1945 s sheets-sheet 1July 8, 1952` l.. J. scHlLLlNG ELECTRIC ENCE ENERGIZER 3 Sheets-Sheet 2Original- Filed Nov. 26, 1945 AAM wwwA :01|Siinnnwbhnf\ July 8, 1952 L..J scHlLLlNG 2,602,844

ELECTRIC FENCE ENERGIZER Original Filed Nov. 26, 1945 5 Sheet-Sheet 5-yg MM@ Patented July 8, 1952 ELECTRIC FENCE ENERGIZER Lorell JohnSchilling', Galesville, Wis., assignor to Babson Bros. Co., acorporation of Illinois Original application November 26, 1945, SerialDivided and this application December 14, 1949, Serial No. 132,880

(Cl. 175-373l 2 Claims. 1

'I'his invention relates to an electric fence energizer, and moreparticularly to an improved battery operated arrangement forperiodically energizing an electric fence wire.

This application is a division of my copending application entitled"Electric Fence Energizer, filed November 26, 1945 as Serial No.630,811, now abandoned.

Electric fences are intended to stop animals, and keep them within adesired enclosure, by the effect of electrical shocks rather than bysheer mechanical strength, the shock used being strong enough to causethe animal to avoid the fence after it has been shocked once or twice,but not strong enough seriously to injure the animal or' anyoneaccidentally coming in contact with the fence wire. Where the fence wireis briefly periodically energized it has been determined that, forreasons of safety, the maximum current deliverable to the fence shouldnot exceed 25 milliamperes at any time, and the shock impulse durationshould not exceed 1%; of a second nor be more often than once a second;and certain states have incorporated these and similar requirements intheir` codes. Accordingly, fence energizing devices for providing abrief periodic impulse to the fence incorporate a circuit interrupter orswitch actuated by timing means in such manner that the shock impulsehas less than 11u second duration and occurs less than sixty times perminute, usually in the neighborhood of 50 impulses per minute.

Previous electric fence energizers of the periodic type designed forbattery operation have almost without exception incorporated amechanical timing arrangement using a moving mechanical mass ofconsiderable inertia (as a pendulum or a large balance wheel) briefly toclose a pair of open contact'points periodically with a cycle determinedby the 'natural period of the mechanical mass. SuchA arrangements havehad a number of defects and objections. One of the principal defects isthat the open contact points have been subject to pitting, corrosion,interruption dueto dirt getting between them, and the like; and the verynature of the timing actuation arrangement has been such that contactshermetically sealed in an appropriate glass tube or other envelope couldnot be used.

I have devised and am here disclosing an electric fence energizerparticularly designed for battery operation which incorporates a noveltiming system adapted, where desired, to use hermetically sealedcontacts; land whichrelies on electrical rather than mechanical factorsfor regulation of the timing. In general, this phase of my inventioncomprises the use of a transformer with a winding of a large number ofturns on a magnetic core structure of considerable weight and size, sothat the inductance of the winding is large enoughto require more than asecond for current build-up to maximum when the winding is connected tothe D.y C. source. as a battery; and then by providing actuating means(as an armature acted uponvby a portion of the flux in the corestructure) operable as a function of the current and field strengthbuild-upr briefly to open the switch. As may be readily apparent, thismakes timingvsubstantially entirely a function of design of the windingand core structure (factors which do not vary in the field) and providesan arrangement which can readily make use of hermetically sealedcontacts in small,

light switches. l

Another important feature of the electric fence energizing system heredisclosed is that it provides means for delivering avery high peaked,steep wave front, relatively slowly decreasing voltage shock impulse tothe fence, having excellent stock stopping power for a given quantity ofelectricity (some states limit-the impulse to 3 milliampere-seconds)Still another feature of this invention is that I make use of anauto-transformer having the above and other desirable characteristics,and associate with it means for preventing variations in load conditionson the fence (as contact of the fence by wet weeds or the like) fromhaving any substantial effect upon the current drain on the battery.Other features and advantages will be apparent from the followingspecification and the drawings, in which:

Fig. 1 is a side elevational View of one embodiment of a battery fenceenergizer incorporating .my inventions; Figj2 is a vertical sectionalView of the device shown in Fig. l, along the line 2-2 of suoli figure;Fig. 3 is a top planview vof the device; Fig. 4 is a horizontalsectional view'along the line 4 4 of Fig. 2; Fig. 5 is anl enlargedvertical view, partly in section, of certain'of the apparatus shown inthe upper part of Fig. 2; Fig. 6 is a schematic diagram illustrating thecircuit used in the device; Fig. 7 is a schematic drawing illustratingstill another system embodying my inventions; Fig. 8 is a sideelevational view of the operating portion of another fence energizingsystem incorporating my inventions; Fig. 9-is a side elevational view,partly broken away, of still another operating' portion embodyingmyinventions; and Fig. l0 .is a fragmentary horizontal sectional viewalongthe line I-lll of Fig. 9. 1

In the particular embodiment of my invention illustrated in Figs. 1-6inclusive, the electric fence energizer comprises a lower battery casingportion consisting of an upper section l) and a lower section II heldtogether in any suitable manner, as by threading a stud I2 into aninternally threaded central member I3 attached to the upper casingsection IIl. The particular arrangement here .shown is designed toaccommodate four I1/2 volt dry cells of the so-called No. 6 size, two ofthese cells being identified as I4 and I5; and proper separation betweenthe cells is ensured by four spacer members at right angles to eachother, the two shown in dotted lines in Fig. 2 being identified as I6and I'I. In the particular arrangement here being disclosed the cellsare all connected in parallel by a contact system arrangement includingthe lower leaf spring contacts (as those identied as I8 and I3) and theupper spring-pressed cup contacts (as those identied as and 2|) adaptedto make contact with the central terminals of the cells, as theterminals Illa and I5a. While this arrangement is shown asrepresentative and as illustrating one whichI have actually built andused, it will be understood that any desired source of relatively lowvoltage direct current can be used, normally either a 11A-2 volt or 6volt battery arrangement. My inventions reside primarily in theoperating apparatus energized by the direct current source, and theapparatus can be designed to operate with any convenient predeterminedbattery arrangement. I prefer this particular arrangement because myAapparatus is fully capable of operating on 11/2 volts (in fact I haveoperated it satisfactorily with a single small ilashlight cell) and thisbattery arrangement results in exceedingly long life of the batterysince, as will become apparent later, there is an almost continuous butexceedingly low current drain on the batteries.

The upper portion of the electric fence energizer now being describedcomprises a lower casing section of metal or similar suitable materialhere identied as 22, and an upper casing section 23 which I prefer tomake of glass, as illustrated, as this enables the indicator lamp 24 tobe mounted Within the casing and also enables the user to watch theoperation of the switch indicated in general as 25. While it is possibleto develop the shocking voltage between two parallel insulated wiresstrung as a fence it is conventional todevelop the energizing voltagebetween a sing-le. insulated fence wire and ground.v kIn the particularsystem shown here one side of the output is grounded by a ground wireconnected to the terminal 26 and the other side of the output isdelivered to the hot terminal 21 supported by a suitablek insulator suchas porcelain andthe like. While a iixed indicator arrangement is' shownin the circuit diagram for simplicity of illustration, an indicatorarrangement of the kind shown in Pfanstiehl Patent 2,304,954, ofDecember 15, 1945, may be used, the rotatable knob 28-being for thispurpose. The upper glass casing part 23 is adapted to seat on a gasket'-of rubber or other suitable material. and the casingparts 22 and 23 areheld together-by suitable means, as by a clamping ring 30.

Referring now more particularly to Figs. 4-6, the operating portionfofthis particular electric fence energizer will Vbe described. In order toprovide a satisfactory shock impulse on the fence it is necessary tostep the low voltage of the source up to a very much higher voltage forthe shock impulse, preferably a voltage reaching a peak in theneighborhood of 50G-1,509 volts and tapering Off relatively slowly.While other battery fencers on the market do this by use of a high ratiostep-up transformer, I nd that much improved voltage curve'characteristics ci the shock impulse can be obtained by delivering theimpulse from the surge eifect incident to the sudden collapse of a eldaround a coil having a large number of turns, as from several hundredturns up to a couple of thousand turns or more. Accordingly I provide anauto-transformer or single winding transformer here shown as comprisingthe core structure 3l having two cuter leg portions Sla and SIb and acentral les portion 3Ic. Adjacent one side of this central leg portion3Ic, and preferably separated therefrom by a thin sheet of insulatingmaterial 32;

is an auxiliary core structure portion comprising a single piece ofstrap metal Sid having an air gap therein between hollow generallyconical pole face portions 3Id and 3Id. The main core structure portionis comprised of a substantial set or stack of laminations of metal ofsuitable magnetic permeability; and the lauxiliary portion 3Id is alsoof magnetically permeable material as soft iron. Around the central leg3Ic of the main core structure portion and the vertical leg of the strapiron portion Bld is a winding or coil 33 of at least several hundredturns and of a resistance of the order of at least several ohms. l Y

Referring now more particularly to the circuit diagram comprising Fig.6, the relatively low voltage direct current source (illustrated as thesingle battery I4 for simplicity) has one side thereof connected toground and to one end of the winding 33 (the lower end as illustrated inthe figure here being described). The other side of the battery I4 isconnected through an onoi switch 34 to one terminal 25a of the switch25, the other terminal 25h being connected to the other end of thewinding 33. In order to prevent arcinga condenser 35 is shunted acrossthese terminals; and the circuit between these terminals is made andbroken within a hermetically sealed glass tube or envelope 25o by therise and fall of level of a pool of mercury 25d. This rise and fall ofmercurylevel is effected by movement of a displacement member 25eattached to a core 251 of magnetically permeable metal, as soft iron.The core 25j and displacement member 25e drop to the position shown inFig. 6 by gravity, causing connection between the terminals 25a and 25hand completion of a circuit through the winding 33. When the current inthis Winding, and the iluX conditions inthe magnetic structure which area function thereof, have reached a predetermined value, the forcedeveloped by the iiux passing between the core portions or pole faces3Id and V3Id is suicient to start upward movement of Athe core 25f, suchupward movement (once started) continuing until the core member 25] iscentered with respect to the gap between the pole faces. This movement,of course, raises the displacement member 25e up out of the mercury pooland causes the mercury level to drop to a point breaking the connectionbetween the terminals 25a and 25h. This causes a sudden collapse of thefield around the winding 33 and develops a surge impulse of relativelyhigh peak voltage and sharp wave front characteristics, providing animproved shock impulse. The particular switch shown and described herehas a number of advantages in itself, but it will not be fully describedand claimed here as it forms the subject matter of my copendingapplication Serial No. 597,991, eldJune 7, 1945,

now abandoned. v V

In order toprevent short circuit conditions on the fence, or loadconditions'providing a relatively low resistance path between the fencewire and ground, from drawing current unduly from the battery during the"charging portion of the Cycle of operation, I connect the hot end ofthe winding 33 to the fence wire through a resistor 36. While a neonlamp with suitable voltage breakdown characteristics could be used, Ifind that this has a tendency to cause a rounding over of the top of thevoltage wave; and accordingly I prefer to use a resistor of severalhundred ohms, as 500 ohms. Also, to provide the desired indication byilashing of the glow lamp 24, I. tap off from a portion of the winding33 to provide an indicating circuit comprising the lamp 24 and a currentlimiting resistor 31 of suitable value, as for example 6,000 ohms. Whilethe condenser 35 may be of any suitable value I find .02 microfaradssatisfactory.

As will be readily apparent, the time interval between closing of thecircuit between the battery I4 and winding 33 and the time when themagnetic pull between the pole pieces 31d and Bld has reached a valuecausing movement of the core piece 25j and breaking of the circuit is afunction of the rise in current in the winding and magnetic densities inthe core structure.

These in turn, of course, are substantially entirely a function of thenumber of turns of the winding and its resistance, and of the amount ofpermeable metal in the core structure, more turns and more metalproviding a longer time interval before the circuit reopens. In order toensure breaking of the circuit I prefer to so construct the switch andassociated pole pieces that opening of the switch takes place wellbefore the current and flux densities have leveled off at their maximum.For example, I find that if I design an auto-transformer in relation tothe 11/2 volt source here illustrated such that current flow andmagnetic conditions do not reach their maximum and level off until about`1.3 seconds, very satisfactory and reliable operation is secured withthe switch having its parts so'proportioned that the circuit is openedatslightly over one second, as about 1.1 second, after it is closed. Asatisfactory transformer providing the desired output impulse and havingappropriate delay characteristics in the build-up of current flow andfield density values, for example, comprises a winding of 1,000 turns ofNo. 20 enameled wire on a core structure of the type illustrated having6 lbs., 5 oz. of iron. I have found that` this provides about 1,400volts peak output with a switch set to open when the current :flow hasreached about 130 milliamperes, with suitable voltage for the indicatinglamp 24 being provided by tapping oif at about 150 turns. Thisarrangement provides a very stable and satisfactory timing system forelectric fence energizing equipment, provides an improved sharp wavefront shocking impulse of the order of a few hundredths of a second orso duration about 50 or 52 times a minute, under conditions whichprovide the utmost in battery life-and which maintains stability oftiming from initial battery voltages clear on down to half voltageconditions or thereabouts. The particular winding specifications givenimmediately above are for copper 6 wire and an. energizing voltageprovided by a single dry cell, nominally 1,1/2 volts; and it will beunderstood that suitable conditions require higher resistances wherehigher voltages are used.

For example, a transformer design which I have found very satisfactoryfor use with a 6- volt direct current source of the type comprising fourlarge dry cells grouped together in a single unit comprises 2,000 turnsof No. 24 copper wire on a 11/2 x 21/2 core structure of approximately 7lbs. in weight. The winding in this case has a resistance of about 46ohms as contrasted with a resistance of only 4 or 5 ohms in the windinggiven above as a suitable example of an autotransformer for use from a11/2 volt source. Inasmuch as the batteries in the volt unit'l are inseries rather than in parallel,A I prefer to use a good deal more thanfour times the resistance in order to keep the current drain per cellwithin desirable limits.

Referring now more particularly to Fig. 7, another embodiment of myinvention will be described. In order to simplify the specication andkeep the description as brief as possible reference numerals 40 higherthan those used in the description of the first form will be applied toanalogous parts in Fig. 7 so that reference back to the precedingdescription may readily be made to supplement this. l

In Fig. 7 the auto-transformerfcomprising the winding 13 and corestructure '1I serve. solely to provide the high voltage shock impulsefor the fence wire, through the resistor 1,6 whenthe energizing circuitis broken; buty actuation of the switch is completely independent of theflux in the main coil, although still a function of the current throughits winding. In this form of my invention the battery 5ft,l which may beof the six-Volt dry-cellv type, has yone end connected to ground and toone endof the winding 13, and the circuit from the other end of thewinding 13 is completed through a switch 55 and a winding 8S back to theother Vside of the battery. Thevwinding 86 is completely separate fromand not magnetically coupled to the winding 13, but is wound about therleg of al U-shaped separate magnetic core structure 81. The rate atwhich the inductance of these coils and principally the inductance ofthe coil 13, enables the current in the series circuit to risedetermines the magnetic force created at the pole faces of the U-shapedmember 81. The switch 65 is herewith shown as provided with twodroplets of mercury in engagement with the contact portions 65a and 65h,these droplets being bridged by the combined circuit closing andarmature member 551. When the magnetic pull developed by the pole facesof the U-shaped member 81 has reached a predetermined value, thearmature member 65 is lifted up at one end, breaking the circuit. lWhiledifferent types of switch arrangements are being illustrated anddescribed to show the flexibility of use of my inventions, thisparticular embodiment is being illustrated in Fig. 'I primarily to showthe use of a condenserv 88 in parallel with the coil 86 as means forpreventing undesirably rapid reclosing of the switch. During thecharging period of a second or slightly over the condenser 88accumulates a voltage, which as soon as the switch B5 opens,'dischargesthrough the winding 86 in a direction tending to continue to hold theswitch contacts open. This comprises a specific way of maintaining theswitch open for a suflicient period to permit comaeoae/ia pletedischarge of the energy stored in the main auto-transformer winding 73.

Still another embodiment of my invention is illustrated in Fig. 8,reference numerals |39 higher than those used in the description ofFigs. 1-6 being applied to analogous parts. In this embodiment of myinventions the main magnetic core structure |3| again has the winding|33 on its central leg. In this case, however, the switch |25 is of themoving mercury-droplet type, adapted to be actuated between open andclosed conditions by tilting of its aXis. It is mounted on a combinedarmature and lever member here identiied as |46, this member beingspring mounted so as to be rockable about the axis provided by the knifeedge portion 24E-d. In this particular form `oif my inventions the fluxleakage to actuate the member 246 is provided by a slot with the facesl3la. and lilla. in the leg Isla, of the core structure. When the fluxleakage has reached a predetermined value the lefthand end of the member|46 (speaking with respect to the position of the parts as shown in Fig.8) is pulled down against the core structure, the switch tube tilts tothe left, and the mercury droplet |2511 runs to the left end of thetube, opening the circuit. The desirable delay in reclosing is providedby the mechanical inertia of the returning of the mechanical parts andthe time required for the mercury droplet |25@ to run back down intoengagement with the terminals |25a, and |2212.

In order to get suicient inductance and time delay to have a period of asecond or more before the switch reopens, however, it is desirable tohave a magnetic core structure which is well closed, so that a completetransverse slot across one leg, as shown in Fig. 8, requires more ironand more turns than would otherwise be necessary. In order to enableactuation of the switch by leakage flux in a portion of the main core,and yet to keep the magnetic circuit provided by the main core of as lowreluctance as possible, I prefer the alternative arrangement shown inFigs. 9 and 10` to that shown in Fig. 8. This ernbodiment of myinventions shown in Figs. 9 and 10 will be described with the use ofreference numerals |40 higher than those used in the description ofFigs. 1-6 applied to analogous parts.

In this electric fence energizing arrangement a magnetic core structureI1| again has its central leg I'Hc surrounded by a winding |73 of atleast several hundred turns, as is the case in all of the embodimentsshown in this application. The leg Illa of the core is provided with aslot which extends only part away across the full width of this leg toprovide pole faces Illa and 'i la dening an air gap in the structuretherebetween. Immediately above this air gap is a movable armaturemember |86 here shown as carrying a contact member |81 adapted to engagea fixed contact |88, although it will be understood that a mercuryswitch of the type shown in Fig. 8, or any other suitable hermeticallysealed switch arrangement, may be employed. The member |86 is mounted onthe leaf spring member |89 and adjusted by means of the nut |9011 on thethreaded stud |9519. As before, the timing is regulated by theinductance of the coil provided by the large number of turns on thewinding and the considerable weight of magnetically permeable metal inthe core structure; and when the current in the winding has reached apredetermined value the magnetic force at the partial air gap in thecore leg Illa attracts the armature member |86 to break the circuitenergizing the winding |13 and cause the collapse of the eldtherearound, providing the desired impulse on the fence wire.

While I have shown and described certain embodiments of my invention, itis to be understood that it is capable of many modiiications. Changes,therefore, in the construction and arrangement may be made Withoutdeparting from the spirit and scope of the invention as disclosed in theappended claims.

I claim:

1 'In an electric fence system, energizing apparatus including; anautotransformer having a winding of the order of a thousand turns ormore; a magnetic core structure of permeable material of a Weight of theorder of six pounds or more, said core having a leg upon which saidwinding is mounted and an external leg having a leakage air gapextending at least partially therethrough; an armature mounted inbridgingrelationship to said air gap and biased away from said core;iirst and second switch contact members, at least one being operativelyconnected to said armature to be moved thereby, a circuit connectionbeing completed between Contact members in the (ie-energized position ofsaid armature; a low voltage dire-ct current source with one terminalconnected to one end of said autotransformer and the other end connectedthrough the normally closed contacts to the other end of saidautotransformer, one end of said transformer being connected to theoutput terminal of the apparatus, said armature and switch contactmembers being Operated directly iux in said core produced solely bycurrent from said source lowing through said winding, whereby the timingof the operation of said fence energizing apparatus is a function or"the slow build-up of current in said winding of the order of a second intime and is relatively independent of variable factors in the use of thedevice.

2. Apparatus of the character claimed in claim l, wherein the connectionbetween one end of the transformer and the output terminal of theapparatus is completed through a resistance of the order of severalhundred ohms.

LORELL JOI-IN SCHILLING.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS OTHER REFERENCES Electromagnetic Devices, page342, by H. C. Rotors, New York, John Wiley & Sons, 1941.

Transformers, pp. II-50-56 incl., by W. C. Sealey, Int. Textbook C0.,Scranton, Pa., 1948.

